Long-term outcomes and predictive factors for survival in premenopausal breast cancer treated with tamoxifen

INTERVENTION: The SBII:2 BioLong study is based on a prospective multicenter randomized clinical trial with > 30 years of follow‐up of adjuvant tamoxifen We will collect formalin‐fixed archival tissue for gross evaluation of tumour‐infiltrating lymphocytes, characterization of them and assessment of lymphovascular invasion in relation to the primary outcome. RNA and DNA will be extracted to enable RNA profiling by PAM50 and additional gene expression analysis with the 360TM panel. Mutational analysis is scheduled to include ESR1, p53, FGFR and PI3K to identify mutations of importance for tamoxifen resistance. The PAM50 and Risk of Recurrence has been thoroughly evaluated on tumors from postmenopausal patients allocated to hormonal therapy and provides additional prognostic information to conventional prognostic markers. Data on prognosis by PAM50 for premenopausal women is sparse and restricted to less than 10 years of follow up. Surrogate subtyping will additionally be compared to the intrinsic subtypes in terms of prognostic capacity The original SBII:2 trial (1986‐1991) is unique as its inclusion was restricted to premenopausal patients and the control arm includes patients without any systemic therapy, the intervention arm received two years of therapy with tamoxifen. The 30 years of follow‐up regarding breast cancer mortality, breast cancer‐free interval (BCFi) and distant recurrence‐free interval (D‐RFi) has been published. The SBII:2 BioLong study will add important genomic and histopathological data to improve our knowledge on factors of importance for long‐term prognosis in premenopausal patients. CONDITION: Premenopausal patients with invasive breast cancer ; Cancer ; Malignant neoplasm of breast PRIMARY OUTCOME: BCFi (Breast cancer free interval) over the 30 year period, measured using patient notes SECONDARY OUTCOME: ; 1. D‐RFi (Distant Recurrence Free interval) over the 30 year period, measured using patient notes; 2. Breast cancer mortality over the 30 year period, measured using patient notes; 3. Overall mortality over the 30 year period, measured using patient notes; INCLUSION CRITERIA: Patients radically operated for invasive breast cancer stage II in the SBII:2 trial